A recent news item raised a similar question about obscenity laws in Washington State. The article implied that only Child Pornography (which is defined in Federal law) is illegal there, at least in terms of what can be viewed on a computer in a public library. So I did the best I can, as a non-lawyer, to look into that law.
While the Wisconsin exemption is longer and more protective of the mission of libraries, the Washington law is impressively concise. Referring to much of Washington's obscenity law as "RCW 9.68.050 through 9.68.120," that law limits its own applicability:
Nothing in RCW 9.68.050 through 9.68.120 shall apply to the circulation of any such material by any recognized historical society or museum, the state law library, any county law library, the state library, the public library, any library of any college or university, or to any archive or library under the supervision and control of the state, county, municipality, or other political subdivision.One of the things that causes confusion in debates about library censorship is that there is no nationwide standard for defining what is illegally obscene, let alone who can or cannot distribute, display, or receive such materials. When it comes to obscenity and public libraries, it is quite possible, even common, that a specific item that is illegal in one jurisdiction is perfectly legal in another. The notable exception is Child Pornography - material that depicts real minors in a sexual way - which is illegal everywhere, controlled by Federal law rather than states, counties, or municipalities.